U.S. patent application number 16/426897 was filed with the patent office on 2019-12-05 for electrode array, a lead paddle and a neuromodulation system.
The applicant listed for this patent is GTX medical B.V.. Invention is credited to Bert Bakker, Jocelyne Bloch, Marco Capogrosso, Gregoire Courtine, Sjaak Deckers, Vincent Delattre, Damien Ganty, Nathan Greiner, Karen Minassian, Edoardo Paoles, Fabien Wagner.
Application Number | 20190366077 16/426897 |
Document ID | / |
Family ID | 62492478 |
Filed Date | 2019-12-05 |
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United States Patent
Application |
20190366077 |
Kind Code |
A1 |
Capogrosso; Marco ; et
al. |
December 5, 2019 |
ELECTRODE ARRAY, A LEAD PADDLE AND A NEUROMODULATION SYSTEM
Abstract
The present invention relates to an electrode array for
neuromodulation, comprising a first electrode section with more
than two electrodes being arranged parallel and densely packed in
the first electrode section, further comprising a second electrode
section with more electrodes than in the first electrode section,
the electrodes in the second electrode section being arranged
symmetrically with respect to the longitudinal axis and transversal
offset to each other. Furthermore, the present invention relates to
a lead paddle and a neuromodulation system.
Inventors: |
Capogrosso; Marco;
(Lausanne, CH) ; Wagner; Fabien; (Lausanne,
CH) ; Courtine; Gregoire; (Lausanne, CH) ;
Delattre; Vincent; (Eindhoven, NL) ; Minassian;
Karen; (Vienna, AU) ; Bakker; Bert;
(Eindhoven, NL) ; Bloch; Jocelyne; (Paudex,
CH) ; Greiner; Nathan; (Lausanne, CH) ; Ganty;
Damien; (Eindhoven, NL) ; Deckers; Sjaak;
(Eindhoven, NL) ; Paoles; Edoardo; (Eindhoven,
NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GTX medical B.V. |
Eindhoven |
|
NL |
|
|
Family ID: |
62492478 |
Appl. No.: |
16/426897 |
Filed: |
May 30, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/0553 20130101;
A61N 1/36062 20170801 |
International
Class: |
A61N 1/05 20060101
A61N001/05 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2018 |
EP |
18175117.3 |
Claims
1. An electrode array for neuromodulation, comprising: a first
electrode section with more than two electrodes arranged in
parallel and densely packed in the first electrode section; a
second electrode section with more electrodes than in the first
electrode section, the electrodes in the second electrode section
arranged symmetrically with respect to a longitudinal axis of the
array, and with a transversal offset relative to each other.
2. The electrode array according to claim 1, wherein the first
electrode section is arranged at a proximal end of the electrode
array and/or the second electrode section is arranged at a distal
end of the electrode array.
3. The electrode array according to claim 1, wherein the electrodes
in the first electrode section are identical to the electrodes in
the second electrode section.
4. The electrode array according to claim 3, wherein at least one
electrode has a length that is 2.0-4.0 times of a width.
5. The electrode array according to claim 3, wherein all electrodes
of the first and second electrode section have a common
orientation, the common orientation parallel to the longitudinal
axis of the electrode array.
6. The electrode array according to claim 1, wherein the electrode
array has a length that is of 8-14 times of a length of an
electrode.
7. The electrode array according to claim 1, wherein the first
electrode section and the second electrode section are separated by
a gap that is larger than the length of an electrode, a length of
the gap chosen in a range of 100-160% of a length of an
electrode.
8. The electrode array according to claim 1, wherein the
longitudinal axis of the electrode array is in a direction of a
longitudinal orientation of the electrodes, wherein the first
electrode section is symmetrical with respect to the longitudinal
axis and with respect to a radial axis in the first electrode
section, the radial axis perpendicular to the longitudinal axis,
and wherein the second electrode section is symmetrical with
respect to the longitudinal axis and asymmetrical with respect to
the radial axis in the second electrode section.
9. The electrode array according to claim 8, wherein the first
electrode section comprises at least three columns aligned with the
longitudinal axis and/or only one radial row along the radial
axis.
10. The electrode array according to claim 8, wherein the second
electrode section comprises at least three columns aligned with the
longitudinal axis and more than five radial rows.
11. The electrode array according to claim 1, wherein a distance
between electrodes of the first electrode section is less than a
width of an electrode, the distance chosen in a range of 50% to 95%
of the width of the electrode.
12. The electrode array according to claim 1, wherein in the second
electrode section, the electrodes in neighboring columns are
arranged with a transversal offset relative to each other.
13. The electrode array according to claim 12, wherein in the
second electrode section, a distance between neighboring electrodes
arranged in a common column is in a range of 135% to 155% of the
length of the electrode.
14. The electrode array according to claim 1, wherein a total
number of electrodes in the electrode array is 16 electrodes.
15. A lead paddle comprising at least one electrode array, the at
least one electrode array having a first electrode section with a
first number of electrodes arranged in parallel; and a second
electrode section with a second number of electrodes, more than the
first number, arranged symmetrically with respect to a longitudinal
axis of the array, and with a transversal offset relative to each
other.
16. A neuromodulation system comprising: at least one electrode
array; and at least one lead paddle, the at least one electrode
array having a first electrode section with a first number of
electrodes arranged in parallel; and a second electrode section
with a second number of electrodes, more than the first number,
arranged symmetrically with respect to a longitudinal axis of the
array, and with a transversal offset relative to each other.
17. The system of claim 16, wherein electrodes of the first and
second electrode section have a common orientation, parallel to the
longitudinal axis of the electrode array.
18. The system of claim 17, wherein the electrodes of the first and
second electrode section are identical in width and length.
19. The system of claim 18, wherein the second number of electrodes
of the second electrode section are arranged in parallel columns,
the electrodes in neighboring columns arranged with a transversal
offset relative to each other.
20. The system of claim 18, wherein a distance between the
electrodes of the first electrode section is less than the width of
the electrode.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to European
Application No. 18175117.3 entitled "AN ELECTRODE ARRAY, A LEAD
PADDLE AND A NEUROMODULATION SYSTEM," filed May 30, 2018. The
entire contents of the above identified application are hereby
incorporated by reference for all purposes.
TECHNICAL FIELD
[0002] The present invention relates to an electrode array, a lead
paddle and a neuromodulation system.
BACKGROUND AND SUMMARY
[0003] Electrode arrays and lead paddles for neuromodulation,
especially neurostimulation, are for example known from U.S. Pat.
No. 8,108,051 B2, US 2013/0096662 A1, US 2012/0006793 A1 and EP 3
013 411 A1.
[0004] For example US 2008/0269854 A1, US 2005/0113878A1 and
EP2243510 B1 disclose a device for patient therapy with a specific
kind of electrode array, i.e. a lead body suitable for patient
implantation; a connection element carried by the lead body and
positioned to electrically couple to a pulse generator suitable for
patient implantation, and at least three electrical contacts
carried by the lead body and positioned relative to the lead body
to contact patient tissue and deliver electrical signals to a
patient, wherein the spacings between the immediately neighboring
contacts of said at least three electrical contacts are at least 8
millimeters.
[0005] U.S. Pat. No. 9,358,384 B2 discloses a flexible paddle
electrode array which has transverse lines of reduced rigidity or
stiffness at these flex or hinge lines, thereby allowing the
flexible paddle electrode array to flex or deflect along its length
at these hinge lines. Because of the living hinges, the staggered
arrangement of the rows of the nonflexible and flexible electrodes,
and the flex or hinge lines, the flexible paddle electrode array is
able to flex along its length, but to be sufficiently rigid to
maintain the nonflexible and flexible electrodes in adequate
contact with patient tissue.
[0006] It has been found that depending on the implantation site of
an electrode array being used and adapted for e.g. spinal cord
stimulation, the way of arranging the electrodes influences the
neuromodulation, especially the neurostimulation outcome and
result.
[0007] It is therefore an object of the present invention to
provide an electrode array, a lead paddle and a neuromodulation
system, which is more adapted and suitable for the stimulation of
the spinal cord, the spinal segments and dorsal roots.
[0008] This object is solved according to the present invention by
a lead paddle positioning and/or deployment system with the
features of an electrode array for neuromodulation.
[0009] Accordingly, an example electrode array for neuromodulation,
comprises: a first electrode section with more than two electrodes
being arranged parallel and densely packed in the first electrode
section, and further comprising a second electrode section with
more electrodes than in the first electrode section, the electrodes
in the second electrode section being arranged symmetrically with
respect to the longitudinal axis and with a transversal offset to
each other.
[0010] The invention is based on the basic idea that with the
combination of the first and the second electrode section two
different means for specifically evoking targeted pools of motor
neurons are provided. By means of an increased density of
electrodes in the first section of electrodes, e.g. positioned in
an application for spinal cord stimulation above the sacral level
of the spinal cord in spinal cord stimulation, a current steering
possibility may be provided to enhance stimulation specificity. In
particular, a so-called electrode belt can be established with the
more than two electrodes being arranged parallel and densely packed
in the first electrode section. The stimulation with an electrode
belt allows a well-defined (current steering) stimulation at the
sacral level and can potentially target any desired spinal segment
located above ("belt array" strategy). The "standard" regular
paddle design configuration in the second electrode section is
provided with regularly spaced electrodes for targeting dorsal
roots at their entry point in spinal segments.
[0011] The electrode array may be configured and adapted for
implantation into mammals, in particular human patients.
[0012] The electrode array be arranged for Central Nervous System
(CNS) Stimulation. In particular, the electrode can be designed for
the stimulation of the spinal cord.
[0013] It is possible to provide neuromodulation and/or
neurostimulation with the electrode array to the CNS. CNS
Stimulation can be done by Epidural Electrical Stimulation (EES)
(or similarly subdural stimulation, hereinafter always to be
understood as possible alternative to EES). Epidural Electrical
Stimulation (EES) is known to restore motor control in animal and
human models and has more particularly been shown to restore
locomotion after spinal cord injury by artificially activating the
neural networks responsible for locomotion below the spinal cord
lesion (Capogrosso, M, et al., A Computational Model for Epidural
Electrical Stimulation of Spinal Sensorimotor Circuits, Journal of
Neuroscience 4 Dec. 2013, 33 (49) 19326-19340, Courtine et al.,
Transformation of nonfunctional spinal circuits into functional
states after the loss of brain input, Nat Neurosci. 2009 October;
12(10): 1333-1342. Moraud et al, Mechanisms Underlying the
Neuromodulation of Spinal Circuits for Correcting Gait and Balance
Deficits after Spinal Cord Injury, Neuron Volume 89, Issue 4, p
814-828, 17 Feb. 2016). EES does not directly stimulate
motor-neurons but the afferent sensory neurons prior to entering
into the spinal cord. In this way, the spinal networks responsible
for locomotion are recruited indirectly via those afferents,
restoring globally the locomotion movement by activating the
required muscle synergies. The produced movement is functional;
however, due to relatively poor selectivity (network activation
instead of selective targeting of key muscles) the controllability
is low, and the imprecisions hinder fluidity and full functionality
in the potential space of the movement. For example,
neuromodulation and/or neurostimulation of the CNS may be used to
enhance and/or restore the capabilities of the patient as regards
movement, especially in a way that the existing ways of
physiological signal transfer in the patient's body are supported
such that the command signals for body movement or the like still
are provided by the patient's nervous system and just supported
and/or enhanced or translated by the CNS stimulation module.
[0014] Furthermore, it is possible that the first electrode section
is arranged at a proximal end of the electrode array and/or the
second electrode section is arranged at a distal end of the
electrode array. The proximal end is especially the end of the
electrode array, which is considering the implanted situation or
the situation during implantation of the electrode array proximal
than the second electrode section, which is then at the distal end
or in a more distal position. By arranging the first electrode
section close to the proximal end, the belt electrode strategy can
be applied close the entry point or channel, where the electrode
array and its carrier (e.g. a lead paddle) are positioned at and/or
around the spinal cord. A more precise position can be provided
with such a design and arrangement.
[0015] The electrodes in the first electrode section can be
identical. This helps to enhance the effects of the belt array
strategy as outlined above. Also, the steering predictability is
enhanced as identical electrodes with inter alia identical
functionality are used. This increases the predictability of the
stimulation capabilities of the electrodes of the first
section.
[0016] Also, the electrodes in the second electrode section can be
identical. Thus, also in the second section the manufacturing is
simplified and also the predictability of the stimulation result
may be enhanced.
[0017] It is possible that electrodes are identical. By providing
(only) identical electrodes, the manufacturing process may be
simplified. Also, the stimulation behavior becomes more predictable
as the electrodes are more comparable to each other when compared
with an approach, where different forms of electrodes are used.
[0018] The electrodes may have a rectangular stimulation area. The
stimulation area shall be understood as the area, which is
effectively participating in the stimulation, i.e. the area which
can be effectively used to send out stimulation signals and/or
receive stimulation signals or other signals.
[0019] At least one electrode may have a length that is 2.0-4.0
times of the width. This relationship was found to be beneficial in
trials as by this form stiffness in axial direction (i.e. along the
longitudinal axis) of the electrode array and its carrier can be
enhanced. Especially, the length may be 2.5-3.0 times of the width.
An example value for the length could be chosen at around 2.6-2.7
times of the width.
[0020] Example dimensions of an electrode, especially of an
electrode with rectangular form, can be approx. 4.0-6.0 mm length
and approx. 1.3-2.5 mm width.
[0021] All electrodes may have the same orientation. Especially, it
is possible that all electrodes have an orientation parallel to the
longitudinal axis of the electrode array. In case that the
electrodes have a form with a longer extension in one direction
than the other, e.g. oval form, rectangular form or the like, and
by arranging the electrodes all in the same direction, the
stiffness and flexibility of the array of electrodes and its
carrier can be influenced. If, for example, all electrodes have a
form with a longer extension along their longitudinal axis and are
oriented all in the same direction of the longitudinal axis, then
the stiffness in the longitudinal direction is increased, while in
radial direction still more flexibility and elasticity is offered.
Such a design is especially beneficial for electrode arrays to be
placed in the spinal channel for spinal cord stimulation.
[0022] The electrode array may have a length that is of 8-14 times
of the length of an electrode, especially approximately 12 times of
the length of an electrode. For example, if the length is chosen in
a range of 4.00-6.00 mm, then the length of the array may be for
example within a range of 50-70 mm. A suitable width of the
electrode may then be chosen in a range of 10-13 mm. With such
dimensions, sufficient area and volume of the spinal cord may be
stimulated. Several segments of the spine and the respective parts
of the spinal cord may be covered and stimulated this way.
[0023] The first electrode section and the second electrode section
can be for example separated by a gap that is larger than the
length of an electrode, especially wherein the length of the gap is
chosen in a range of approx. 100-160% of the length of an
electrode. A possible setup may be chosen such that the length of
the gap is chosen in a range of approx. 100%. These dimensions have
been found to be beneficial based on the following observations and
consideration: The radiation and stimulation sent out from an
electrode can also reach and stimulate areas adjacent to the
electrode. Thus, also electrodes can be arranged spaced apart from
each other without losing possible coverage of the area/volume to
be stimulated. By choosing the gap in a range of approx. 130-160%
of the length of an electrode still sufficient coverage of the
area/volume to be stimulated can be reached. Also, it is possible
to increase the overall length of the electrode in the longitudinal
direction, which is beneficial especially in the field of spinal
cord stimulation. So, a longer segment of the spinal cord can be
covered and stimulated with the electrode array.
[0024] The electrode array can for example comprise a longitudinal
axis in the direction of the longitudinal orientation of the
electrodes, wherein the first electrode section is symmetrical with
respect to the longitudinal axis and with respect to a radial axis
in the first electrode section perpendicular to the longitudinal
axis. Symmetry in this section helps to increase the steering
capabilities and the electrode belt stimulation strategy.
[0025] Alternatively and/or additionally it is possible that the
second electrode section is symmetrical with respect to the
longitudinal axis and asymmetrical with respect to a radial axis in
the second electrode section perpendicular to the longitudinal
axis. Asymmetry is the second electrode section is helpful to
achieve greater coverage of area/volume to be stimulated with the
electrodes arranged in the second electrode section.
[0026] Although the second electrode section may be in that
asymmetrical, the pattern of the electrodes in this section may
still be a regular one, i.e. that the distance of neighboring
electrodes and the arrangement of neighboring electrodes always
stays the same (or more or less the same) in the second electrode
section.
[0027] The first electrode section can comprise at least 3 columns,
preferably at least four or five columns, aligned with the
longitudinal axis and/or only one radial row along the radial axis.
Three or more columns have found to be sufficient to establish
successfully an electrode belt array strategy. Preferred setups
comprise four or five columns. No further radial row has been found
to be necessary.
[0028] The second electrode section can comprise for example at
least 3 columns aligned with the longitudinal axis and more than 5
radial rows, preferably more than 7 rows, especially at least 8
rows. With such an arrangement, more coverage in longitudinal
direction than in radial direction can be provided. This is
especially beneficial in spinal cord stimulation, where in the
spinal channel it is desirable to stimulate the spinal cord over a
substantial part of the spinal cord and over several segments. In
other words, one can say the longer the electrode array, the better
it is for spinal cord stimulation.
[0029] The distance between electrodes of the first section can be
for example less than the width of an electrode chosen in the range
of approx. 50% to 95% of the width of an electrode, especially
approx. 55-75% of the width of an electrode. A possible setup may
be chosen such that the width of an electrode chosen in the range
of approx. 55% of an electrode. By this, a dense packing of the
electrode can be provided. Also, still the steering of the
stimulation and the stimulation overlap can be managed very
precisely.
[0030] Furthermore, for example in the second electrode section the
electrodes in neighboring columns can be arranged to each other
with a transversal offset. With such a transversal offset a good
stimulation area coverage can be established. Also, in this way
more coverage in for example the longitudinal direction with some
coverage in radial direction can be provided with less
electrodes.
[0031] Furthermore, in the second electrode section the distance
between neighboring electrodes (or distance between neighboring
contacts/electrodes or the distance to the neighboring
contact/electrode) arranged in the same column can be for example
chosen in the range of 135% to 155% of the length of an electrode,
especially in the range of 140% to 150% of the length of an
electrode.
[0032] Moreover, additionally and/or alternatively in the second
electrode section the distance between neighboring rows can be
chosen in the range of 130% to 150% of the width of an electrode,
especially in the range of 135% to 145% of the width of an
electrode.
[0033] These ranges have been found to be beneficial to achieve the
aim of providing sufficient stimulation coverage in for example the
longitudinal direction with some coverage in radial direction with
less electrodes.
[0034] For example, the electrode array may comprise a number of
electrodes chosen in the range of 8-32 electrodes, preferably 14-18
electrodes, most preferably 16 electrodes. It has been found that a
number of electrodes chosen in the range of 10-20 electrodes allows
sufficient precise stimulation and at the same time is good to
handle in terms of complexity of the electronic system. The range
of 14-18 electrodes has been found to be advantageous, as in this
range steering and precise stimulation is possible. 16 electrodes
appear to be the best compromise in steering capabilities,
preciseness of the stimulation to be provided and also the
area/volume to be stimulated and at the same time still manageable
complexity of the necessary electronic system for the electrodes,
by at the same time reducing side effect. The effects have been
observed during trials (animal tests and clinical trials), which
have not yet been published.
[0035] Furthermore, the present invention relates to a lead paddle
comprising at least one electrode array as defined above.
[0036] The lead paddle may be a lead paddle of a neuromodulation
system, especially of a neurostimulation system.
[0037] Also, the present invention relates to a neuromodulation
system comprising at least one electrode array as defined above
and/or at least one lead paddle as defined above.
[0038] The neuromodulation system can be for example a
neurostimulation system, especially a neurostimulation system for
the stimulation of the spinal cord. In particular, the
neurostimulation system may be a system to provide inter alia, but
not limited to, EES. It can be a combined system that can provide
EES and FES for example.
BRIEF DESCRIPTION OF THE FIGURES
[0039] Further details and advantages of the present invention
shall now be disclosed in connection with the drawings.
[0040] It is shown in
[0041] FIG. 1 a view from above of a possible embodiment of an
electrode array according to the present invention for a lead
paddle and a neuromodulation system according to the present
invention;
[0042] FIG. 2 a side view of the lead paddle and the electrode
array according to FIG. 1;
[0043] FIG. 3 cutaway drawing through the first section of the lead
paddle and the electrode array according to FIG. 1;
[0044] FIG. 4 a schematical drawing of the spinal cord with the
embodiment of the lead paddle of FIG. 1;
[0045] FIG. 5 the lead paddle according to FIG. 1 with further
details.
[0046] It will be appreciated that FIGS. 1-5 show example
configurations with relative positioning of the various components.
Further, the components are shown to scale. If shown directly
contacting each other, or directly coupled, then such elements may
be referred to as directly contacting or directly coupled,
respectively, at least in one example. Similarly, elements shown
contiguous or adjacent to one another may be contiguous or adjacent
to each other, respectively, at least in one example. As an
example, components laying in face-sharing contact with each other
may be referred to as in face-sharing contact. As another example,
elements positioned apart from each other with only a space
there-between and no other components may be referred to as such,
in at least one example. As yet another example, elements shown
above/below one another, at opposite sides to one another, or to
the left/right of one another may be referred to as such, relative
to one another. Further, as shown in the figures, a topmost element
or point of element may be referred to as a "top" of the component
and a bottommost element or point of the element may be referred to
as a "bottom" of the component, in at least one example. As used
herein, top/bottom, upper/lower, above/below, may be relative to a
vertical axis of the figures and used to describe positioning of
elements of the figures relative to one another. As such, elements
shown above other elements are positioned vertically above the
other elements, in one example. As yet another example, shapes of
the elements depicted within the figures may be referred to as
having those shapes (e.g., such as being circular, straight,
planar, curved, rounded, chamfered, angled, or the like). Further,
elements shown intersecting one another may be referred to as
intersecting elements or intersecting one another, in at least one
example. Further still, an element shown within another element or
shown outside of another element may be referred as such, in one
example.
DETAILED DESCRIPTION
[0047] FIG. 1 shows a view from above of a possible embodiment of
an electrode array 5 according to the present invention for a lead
paddle 10 and a neuromodulation system 100 according to the present
invention.
[0048] For better orientation in FIG. 1, a longitudinal axis shall
be understood as being aligned (i.e. identical or parallel to) the
longitudinal direction L.
[0049] A radial axis shall be understood as being aligned (i.e.
identical or parallel to) the radial direction R.
[0050] The lead paddle 10 comprises a lead paddle body 11 and
comprises two guiding channels 12.
[0051] The two guiding channels 12 are embedded in the lead paddle
body 11.
[0052] The lead paddle body 11 may be made of a medical grade
material, such as a medical grade polymer. In particular, a medical
grade silicone or the like may be used.
[0053] The guiding channels 12 extend over more than half of the
length of the length of the lead paddle 10.
[0054] Especially, the guiding channels 12 extend over more than a
half, for example, 80% of the length of the lead paddle 10.
[0055] In particular, the guiding channels 12 are arranged along
the outer edge region 14 of the lead paddle 10.
[0056] In particular, the guiding channels 12 are arranged parallel
to the longitudinal edge 16 of the lead paddle 10.
[0057] The lead paddle 10 comprises a plurality of electrodes 18
forming the electrode array 5.
[0058] Here, in the shown embodiment 16 electrodes 18 are
provided.
[0059] The electrodes 18 are embedded in the body of the lead
paddle 10.
[0060] Each specific electrode 18 has a specific denotation, here
En with n being chosen from 1 to 16.
[0061] The shape of the electrodes 18 is rectangular.
[0062] All electrodes 18 have the identical form. The shape of all
electrodes is more or less identical. Here the electrodes 18 are
all identical in their form.
[0063] The electrodes 18 have a length 1 that is 2.0-4.0 times of
the width w, especially 2.5-3.0 times of the width. Here they have
a length that is approx. 2.6 times of the width to form an elongate
shaped rectangular electrode form.
[0064] Generally speaking, the form of one or more electrodes can
be designed differently. In particular, they can be oval, round,
square, diamond shape, trapezoidal or the like.
[0065] The electrodes 18 form the electrode array 5 for
neurostimulation.
[0066] The electrode array 5 has a length that is of 8-14 times of
the length of an electrode, here in the shown embodiment
approximately 12 times of the length of an electrode 18.
[0067] All electrodes 18 have the same orientation. In particular,
all electrodes 18 have an orientation parallel to the longitudinal
axis of the electrode array 5.
[0068] The electrode array 5 comprises a first electrode section S1
with four electrodes 18.
[0069] The electrodes 18, here the electrodes E5, E6, E15 and E16
of the first electrode section S1 are arranged parallel and densely
packed in the first electrode section S1.
[0070] The first electrode section S1 is arranged at the proximal
end P of the lead paddle 10.
[0071] The first electrode section S1 comprises here four columns
C01, C02, C03, C04 aligned with the longitudinal axis and only one
radial row R0 along the radial axis in this first electrode section
S1.
[0072] The distance between electrodes 18 of the first electrode
section S1 is less than the width w of an electrode 18 chosen in
the range of approx. 50% to 95% of the width of an electrode 18 and
here chosen at approx. 55-75% of the width of an electrode 18.
[0073] A second electrode section S2 is arranged at the distal end
D, i.e. the section orientated to the tip end 17 of the lead paddle
10.
[0074] The first electrode section S1 and the second electrode
section S2 are separated by a gap G that is larger than the length
1 of an electrode 18.
[0075] Here, the length 12 of the gap G is chosen in a range of
approx. 100-150% of the length of an electrode 18.
[0076] In the second electrode section S2 more electrodes 18 than
in the first electrode section S1 are provided, i.e. electrodes
E1-E4, E7-E10 and E11-E14.
[0077] The electrodes 18 in the second electrode section S2 are
arranged symmetrically with respect to the longitudinal direction L
and with transversal offset to each other.
[0078] The second electrode section S2 comprises at least three
columns C1, C2, C3 aligned with the longitudinal axis and eight
rows R1, R2, R3, R4, R5, R6, R7, R8.
[0079] In the second electrode section S2 the distance between
neighboring electrodes 18 arranged in the same column C1, C2, C3 is
chosen in the range of 135% to 155% of the length of an electrode
18, here in the range of 140% to 150% of the length 1 of an
electrode 18.
[0080] Also, in the second electrode section S2 the distance
between neighboring rows R1, R2, R3, R4, R5, R6, R7, R8 is chosen
in the range of 130% to 150% of the width w of an electrode 18,
here in the range of 145% to 155% of the width w of an electrode
18.
[0081] The arrangement of the electrodes 18 is also such that some
electrodes are offset to each other.
[0082] Here, in the second electrode section S2 the electrodes 18
in neighboring columns C1 to C2 and C2 to C3 are arranged relative
to each other with a transversal offset.
[0083] So and as clearly can be seen from e.g. FIG. 1, the
electrode array 5 comprises a longitudinal axis in the direction of
the longitudinal orientation of the electrodes 18, wherein the
first electrode section S1 is symmetrical with respect to the
longitudinal axis and with respect to a radial axis in the first
electrode section S1 perpendicular to the longitudinal axis and the
second electrode section S2 is symmetrical with respect to the
longitudinal axis and asymmetrical with respect to a radial axis in
the second electrode section S2 perpendicular to the longitudinal
axis.
[0084] The electrodes 18 of the lead paddle 10 are connected to
lead bodies 20.
[0085] The lead bodies 20 are connected to a connection portion 20a
on the upper side 10a of the lead paddle 10.
[0086] This connection portion 20a is on the opposite side of the
contact side 10b of the lead paddle 10, that is configured and
arranged to get in contact with the tissue to be stimulated, i.e.
here the spinal cord of the patient.
[0087] Furthermore, the connection portion 20a is arranged centric
with regard to the axial axis of the lead paddle 10. Moreover, the
connection position 20a is positioned with an offset d to the edge
of the proximal end 10c of the lead paddle 10.
[0088] As the connection portion 20a of the lead bodies 20 is not
directly arranged at the outer edge of the lead paddle 10, the
deployment and positioning of the lead paddle 10 is enhanced.
[0089] In particular, the offset d helps that by means of the lead
bodies 20 the lead paddle 10 may be moved back and forth and also
to the left and right and vice versa even after deployment in the
spinal canal. As the lead bodies are arranged on the upper side
with an offset to the edge, the proximal edge of the lead paddle is
free and especially a movement in the proximal direction is not
obstructed by the lead bodies.
[0090] As can be further seen in FIG. 1, the lead bodies 20 can be
provided with anchoring sleeves 22.
[0091] The anchoring sleeves 22 are attached to the outer side of
the lead body 20.
[0092] Furthermore, the anchoring sleeves 22 are provided with pins
24 or so-called anchor bumps 24, which extend radially from the
outer side of the anchoring sleeve 22.
[0093] FIG. 2 shows a side view of the lead paddle and the
electrode array according to FIG. 1.
[0094] As can be seen in FIG. 2, the electrodes 18 protrude out of
the surface of the contact side 10b.
[0095] FIG. 3 shows cutaway drawing through the first section of
the lead paddle and the electrode array according to FIG. 1.
[0096] On the upper side 10a the connection portions 20a of the
lead bodies 20 can be seen.
[0097] Due to the arrangement of the electrodes 18 and the spacing
between the electrodes 18, the form of the electrodes 18, the lead
paddle body 11 and thus the lead paddle 10 comprises axial
stiffness in the longitudinal direction L and radial flexibility in
the radial direction R.
[0098] So, it is generally possible that even without a stylet and
by means of the lead bodies 20 the lead paddle 10 can be inserted
into the spinal channel. For such an insertion axial stiffness is
necessary to avoid bending in axial direction, whereas (slight)
bending in the radial direction is wanted to adapt to the
anatomical structures at the implantation site in the spinal
channel.
[0099] The first electrode section S1 and the second electrode
section S2 provide two different means for specifically evoking
targeted pools of motor neurons.
[0100] FIG. 4 shows a schematical drawing of the spinal column 200
and the spinal cord 210 with the embodiment of the lead paddle 10
with the electrode array 5 as described above.
[0101] By means of the increased density of electrodes 18 in the
first electrode section S1, e.g. positioned in an application for
spinal cord stimulation above the sacral level of the spinal cord
210 in spinal cord stimulation as shown in FIG. 4, a current
steering possibility may be provided to enhance stimulation
specificity. In particular, a so-called electrode belt is
established with the four electrodes 18 (i.e. electrodes E5, E6,
E15, E16) being arranged parallel and densely packed in the first
electrode section S1.
[0102] In FIG. 4 it can been seen that dorsal roots enter the
spinal cord in their respective segment (i.e. C1 root enters at C1
spinal segment). The exit point of the vertebrate column for
lumbo-sacral roots is located rather far apart of their respective
entry point in the spinal cord. Especially, lumbar and sacral roots
overlay each other like a "spaghetti bag" around the conus
medullaris region.
[0103] From this anatomical structure and the needs for stimulation
of these anatomical structures the following specific points are
addressed by the electrode array 5 of the present invention:
[0104] The stimulation with an electrode belt allows a well-defined
(current steering) stimulation at the sacral level can potentially
target any desired spinal segment located above ("belt array"
strategy).
[0105] The "standard" regular paddle design configuration in the
second electrode section S2 is provided with regularly spaced
electrodes for targeting dorsal roots at their entry point in
spinal segments. This is based on the finding that a regularly
spaced electrode array would work well in the cervical area to
specifically address individual spinal segments, but that this
specificity will deteriorate when sliding the array toward sacral
region. Yet, it will still quite sufficient for upper lumbar
segments.
[0106] FIG. 5 shows the lead paddle 10 with the electrode array 5
according to FIG. 1 with further details.
[0107] In particular, FIG. 5 shows in greater detail the dimensions
and the lead paddle 10 with the electrode array 5 with example
values for distances.
[0108] Inter alia, the [0109] distance E between outermost edges of
the electrode array (width) w1 is approx. 11.5 mm, [0110] distance
F between outermost edges of the electrode array (length) l1 is
approx. 65 mm (cf. also FIG. 2), [0111] distance H between the
right outermost edges of two neighboring electrodes 18 is approx.
3.15 mm, [0112] distance I between proximal edge of section S1 is
approx. 13.25 mm, [0113] distance J between proximal edge from R1
to R2 is approx. 6.7 mm, and [0114] distance K from longitudinal
right edge of electrode in C2 to right outer longitudinal edge of
the lead paddle 10 is approx. 6 mm.
[0115] The overall dimensions/size of one electrode 18 is approx.
2.times.5.5 mm with 0.25 mm. In the shown embodiment, a minimum
exposed electrode surface to tissue of at least 10 mm.sup.2 was
required and is reached with this setup, as the exposed electrode
surface of an electrode 18 is approx. 11 mm.sup.2.
TABLE-US-00001 REFERENCES 5 electrode array 10 lead paddle 10a
upper side 10b contact side 10c proximal end 11 lead paddle body 12
guiding channel 14 outer edge region 16 longitudinal edge 17 tip
end 18 electrodes 20 lead body 20a connection portion 22 anchoring
sleeves 24 pins 100 neuromodulation system 200 spinal column 210
spinal cord d offset D distal end E distance between outermost
edges of the electrode array (width) F distance between outermost
edges of the electrode array (length) G gap H distance H between
the right outermost edges of two neighboring electrodes in section
S1 I distance between proximal edge of section S1 J distance
between proximal edge from R1 to R2 K distance from longitudinal
right edge of electrode in C2 to right outer longitudinal edge of
the lead paddle L longitudinal direction P proximal end R radial
direction l length of electrode w width of electrode l1 length of
electrode array w1 width of electrode array l2 length of gap C01
column in first electrode section C02 column in first electrode
section C03 column in first electrode section C04 Column in first
electrode section R0 row in first electrode section C1 column in
second electrode section C2 column in second electrode section C3
column in second electrode section R1 row in second electrode
section R2 row in second electrode section R3 row in second
electrode section R4 row in second electrode section R5 row in
second electrode section R6 row in second electrode section R7 row
in second electrode section R8 row in second electrode section S1
first electrode section S2 second electrode section
* * * * *